• 반도체디스플레이기술학회지
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• 제15권1호
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• pp.36-40
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• 2016

This paper is about the analysis on the vibration characteristic of tooling units on the precision automatic lathe. The vibration characteristic of the machine tool is emphasized in accordance with the high precision of the various industries Including the various semiconductor devices and components sector. In this paper, the vibration analysis was performed in designed tooling units of precision automatic lathe. Through the analysis, it is calculated that the frequency of distribution in certain areas by review the resonant frequency and the amount of deformation. And designed model was verified to be a stable structure.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 춘계학술발표논문집 1부
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• pp.261-264
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• 2010

Fast algorithm is proposed by using mel scale and the distribution characteristic of LSP parameters, and is to reduce the computational amount. Computational amount means the calculating times of transformation from LPC coefficients to LSP parameters. Among conventional methods, the real root method is considerably simpler than other, but neverthless, it still suffer from its indeterministic computational time. Because the root searching is processed sequentially in frequency region. In this paper, the searching interval is arranged by using mel scale but not it is uniform and searching order is arranged by the distribution characteristic of LSP parameters that is most LSP papameters are occured in specific frequency region. In experimental results, computational amount of the proposed algorithm is reduced about 48.95% in average, but the transformed LSP parameters of the proposed method were the same as those of real root method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.701-703
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• 1993

This paper describes characteristic analysis of high frequency inverter using zero voltage switching(ZVS) which is one of the methods to reduce switching loss. This study is generally described by introducing normalized control variables. Moreover, many characteristics of analysis results offer importanat data for circuit design. In addition, the result of its characteristic analysis is compared with that from PSpice's simulation.

• 한국정보통신학회논문지
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• 제11권2호
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• pp.223-228
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• 2007

본 논문에서는 고속 주파수 도약과 높은 주파수 분해도 그리고 광역 주파수 신호를 발생하는 디지털 주파수 합성기를 설계하고 구현한다. 고속 주파수 도약과 미세한 도플러 주파수 보정을 위한 높은 주파수 분해도를 갖는 DDS 기술과 직접 주파수 변환을 위한 광대역 PLL 기술을 적용하여 DVB-RCS 전송을 위한 전송 중간 주파수 신호를 직접 발생하는 주파수 합성기를 구현한다. $2.5{\sim}3.0$ GHz 대역의 500 MHz 사용 주파수 대역내에서 -50 dBc 이하의 스퓨리어스 신호 억압을 제공하고, 0.233 Hz의 세밀한 주파수 분해도와 125 ns 이하의 고속 주파수 도약 특성을 갖는 DFS구조를 갖는다. 또한 제작된 DFS는 광대역 사용주파수 영역에서 3 dB 이내의 이득 평탄도를 나타내었으며, 위상잡음은 1 KHz ?낵쩔【? -75 dBc/Hz의 양호한 특성을 나타내었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.846-851
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• 2005

The purpose of this paper is that investigates the dynamic behavior characteristic of W.T.S(Wind turbine System) and carries out the evaluation analysis during operating W.T.S. To investigate the dynamic behavior characteristic of W.T.S, the experiments to measure vibration of the blade from the attached accelerometer on the flap and edge section of the blade that is one of the most important elements of dynamic characteristic of W.T.S are performed. Natural frequency and mode shape are calculated with commercial program (ANSYS) using the measured vibration acceleration that receives the signal with F.F.T Analyzer from the accelerometer. For validation of these experiments, the finite element analysis is performed with commercial F.E.M program (ANSYS) on the basis of the natural frequency and mode shape. The results indicate that experimental values have good agreements with the finite element analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 전문대학교육위원 P
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• pp.1-3
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• 1999

EM (ElectroMagnetic) pump is used for the purpose of transporting liquid sodium coolant with electrical conductivity in the LMR(Liquid Metal Reactor). (In the present study, pilot EM pump has been designed by using of equivalent circuit method which is commonly employed to analyze linear induction machines for the test of removal of residual heat. The length and diameter of the pump have fixed values of 840 mm and 101.6 mm each by taking account of geometrical size of circulation loop for the installation of EM pump. Flowrate versus developing pressure is related from Laithwaite's standard design formula and the characteristic analyses of developing force and efficiency are carried out according to change of input frequency. From the characteristic curve, input frequency of 13 Hz is determined as the design frequency. On the other hand, The annular air gap size of 6.05 mm is selected not to bring about too much hydraulic loss. Resultantly design analysis makes pump have the electrical input of 604 VA and the hydrodynamical capacity of 1.3 bars and 40 l/min.

• 한국소음진동공학회논문집
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• 제23권12호
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• pp.1082-1089
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• 2013

3-Axis sensor measurement system is needed for measuring ride quality of elevator. But because 3-Axis piezoelectric accelerometer is expensive. We developed 3-Axis sensor system which is suitable for measuring ride quality of elevator using cheap MEMS sensor. There are two types of MEMS sensor that are piezoresistive and capacitive type. The excellence of piezoresistive type in characteristic of frequency response and noise is confirmed compare to capacitive type as a result of this paper's experiment and reference. 3-Axis system using MEMS sensor needs MEMS's proper frequency response characteristic. Additionally noise characteristic of sensor and circuit, stiffness of assembly are needed for deciding frequency range and accuracy of amplitude.

• 한국정보통신학회논문지
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• 제17권5호
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• pp.1055-1063
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• 2013

전자파 내성 및 전자파 장해 측정을 위한 표준 전자파 발생 장치 중 하나인 CTL cell에서 두 개의 입력 단자에 동일 신호와 역위상 신호 입력에 따른 다양한 전계와 자계 발생에 대해 살펴보았다. 기본 공진주파수 TE011이 2.20GHz인 CTL cell을 이용하여 우세 전계장과 우세 자계장 조건에서 입력 전력의 변화에 따른 전계 특성, 측정 위치에 따른 전계 특성, 주파수 변화에 따른 전계 특성을 측정하였고, 이를 이용하여 CTL cell의 측정 영역에서의 동작 특성과 공진주파수의 영향을 받지 않고 사용 가능한 주파수 대역을 살펴보았다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
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• pp.63-65
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• 2004

The recent advancement in the power electronic technique has increased the use of induction motor fed by inverter using high-frequency switching devices. Also the tendency is toward larger size and higher voltage. Therefore, The IGBT (Insulated-Gate Bipolar Transistor) that is high switching frequency element has been using increase. But, The switching surge voltage was occurred by high switching frequency of inverter has appeared a voltage doubling in the motor input terminal due to mismatching of cable characteristic impedance and motor characteristic impedance. Actually, The Switching surge voltage became the major cause to occur the insulation failure by serious voltage stress in the stator winding of induction motor. The short during rise time of switching surge and cable length is increased, the maximum transient voltage seen at the motor terminals increases. In this paper, Analyzed switching surge transient voltage of power cable pulling is used EMTP(Electromagnetic Transient Program) at the induction motor terminal and in cable.

• 한국소음진동공학회논문집
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• 제15권11호
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• pp.1232-1240
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• 2005

The purpose of this paper is that investigates the dynamic behavior characteristic of W.T.S (wind turbine system) and carries out the evaluation analysis during operating W.T.S. To investigate the dynamic behavior characteristic of W.T.S, the experiments to measure vibration of the blade from the attached accelerometer on the flap and edge section of the blade that is one of the most important elements of dynamic characteristic of W.T.S are performed. Natural frequency and mode shape are calculated with commercial program ( ANSYS) using the measured vibration acceleration that receives the signal with F.F.T Analyzer from the accelerometer For validation of these experiments, the finite element analysis is performed with commercial F.E.M program (ANSYS) on the basis of the natural frequency and mode shape. The results indicate that experimental values have good agreements with the finite element analysis.